Lighting control system



March 1944- H. E. LIPPMAN LIGHTING CONTROL SYSTEM Filed April 17, 1940lNVENTOR WITNESSES:

Patented Mar. 28, 1944 UNITED STATES PATENT OFFICE LIGHTING CONTROLSYSTEM Pennsylvania Application April 17, 1940, Serial No. 330,091

13 Claims.

My invention relates, generally, to lighting control systems, and, moreparticularly, to systems for selectively controlling the operation ofrunway marker or contact lights for airports and the like.

Large airports and landing areas for aircraft are usually provided witha plurality of runways for the landing and taking ofi of aircraft, whichextend in different predetermined directions and which are lined ormarked on either side by contact lights usually partially embedded inthe runway surface in spaced relation to project beams with maximumcandlepower approximately degrees above the horizontal, having a narrowvertical divergence and being either uniform throughout all angles ofazimuth or consistin of two main beams emitted in essentially oppositedirections.

The contact lights of each runway are usually operated on a seriescircuit, and heretofore have been operated at a predetermined definitebrightness as determined by a constant current of 6.6 amperes, forexample. It has been determined, however, that it is desirable, and evennecessary in certain instances, to change or vary the brightness Of thecontact lights to conform to various degrees of atmospherictransmissivity for the reason that at normal light output the brightnesswill be too great during clear weather, of about the correct brightnessduring light fog, and inadequate during heav fOg or when visibility isquite low.

Since only one runway is used at a time depending on the wind directionor other factors determining the proper selection of a runway direction,it is also desirable to provide an effective arrangement for selectingthe runway to be lighted and the brightness of the contact lightsthereof by means of a single control system.

Accordingly, it is the object of my invention, generally stated, toprovide a system for selectively controlling the operation of thecontact lights on airport runways.

A more specific object of my invention is to provide for selectivelycontrolling the brightness of a plurality of contact lights associatedwith the runway of an airport or the like.

Another object of my invention isto provide a system for controlling theoperation of contact lights which may be operated to select the contactlighting circuit associated with any one of a plurality of runways, andselect or predetermine the brightness of the contact lights of thecircuit before the circuit is energized.

A further object 01 the invention is to provide for selectivelyoperating any one of a plurality of contact lighting circuits from asingle source of supply and selectivel controlling the brightness of thecontact lights of the selected circuit.

A still further object of my invention is to provide, in a controlsystem of the above-described character, for so interlocking the runwayselector control with the brightness control that neither one may beoperated during the time the selected contact lighting circuit isenergized and in operation without automatically deenergizing theenergized lighting circuit.

Another object of my invention is to provide, in a selection andbrightness control system for contact lighting circuits, forautomatically disconnecting the source of power supply from the circuitin response to failure of the energized lighting circuit.

These and other important objects of my invention will become moreapparent from the following detailed description when read inconjunction with the drawing, wherein the single figure is adiagrammatic view oi a control system embodying the principal featuresof my invention.

In practicing my invention in accordance with one exemplary embodimentthereof, a plurality of series contact lighting circuits are connectedfor operation from a single supply source through a plurality of runwayselector relays, a plurality of brightness control relays, anautotransformer, a constant current regulator, and a main line switch.The runway selector relays are selectively controlled by a runwayselector controller, and the brightness control relays by a brightnessselector controller. These selector controllers function to preselectthe particular runway selector and brightness control relays which willbe operated when a master switch is closed to energize the main lineswitch. The master switch, the runway selector controller, thebrightness controller, and a protective relay device are so electricallyinterlocked that the contact lighting circuit in use will beautomatically deenergized upon the attempted operation of either therunway selector controller or brightness selector controller to adifferent position, and also the protective relay device will functionto open the main line switch upon failure of the contact lightingcircuit which is energized and in use.

Referring to the drawing, the numerals i0, H,

I I2 and I3 designate the contact or runway marker lighting circuits ofan airport, each circuit being associated with a different runway, andthe lamps or lighting units It thereof being connected in series circuitrelation to provide the well-known arrangement of a series lightingcircuit which is usually operated at a predetermined value of constantcurrent on the order of 6.6 am- The lighting circuits may be energizedfrom any suitable power source represented by conductors II and itthrough a constant current regulating transformer ll of well-knownconstruction. The connection of the primary winding of the regulatingtransformer I! to the supply conductors iI and I! may be controlled by aline switch 24 having an operating winding which is remotely controlled,as will be described more in detail hereinafter. In this instance. theseries lighting circuits are all normally connected in series circuitrelation to the supply conductors II and il, although it is to beunderstood that any other suitable circuit arrangement may be used.

In the operation of systems of this kind, it is desirable to provide foroperating any one of the lighting circuits depending upon the runwaywhich is desired to be used, and also to provide for controlling thebrilliancy or brightness of the contact lights in accordance withatmospheric conditions. Under weather conditions where a light fogprevails, the lighting cir it in use may be operated at the normalcurrent value oi 6.6 amperes to produce satisfactory illumination tooperating circuit is partially established for the control relay 24through the conductor 41. 0peration of the drum to positions 1/ and zlikewise partially establish operating circuits for the control relays29 and 22, respectively.

In order to provide for selecting one of the lighting circuits andrendering it effective for operation, a runway selector control 48 isprovided. This control may comprise a plurality of selector relays 49,50, 5i and I2 and a manually operable drum controller 53. Thiscontroller is similar to the brightness selector controller 2!, exceptthat it is provided with an additional contact segment on the drum,making it a four-position controller instead of a three-positioncontroller. as in the case of the controller 31. It comprises a drum 54having segments 55, 56, I1, 58 and 44 enable the pilots of the airplanesto determine the limits of the runway. This normal light output has beenfound to be too bright under clear or more favorable weather conditions,and inadequate during adverse weather conditions, as during a heavy fog.Accordingly. it is desired to provide for operating the lighting circuitat a brightness which is less or greater than the normal value which maybe produced by operating at different values of current above and belowthe normal value.

In this instance, this result is accomplished by utilizing anautocurrent transformer 2i which is connected across the secondary oroutput winding 22 of the regulating transformer H, as shown. The supplyconductor it is connected to one terminal 23 of the autocurrenttransformer, and provision is made for connecting the other supplyconductor it to any one of the current tape 24, 2B and 24. In thisinstance, the tap 25 is the one which is used to produce normal lightoutput or brightness, tap 28 produces a light output or brightness belownormal, and tap 24 a light output or brightness above normal.

The control of the brightness of the lighting circuits may be elected bymeans of the brightness control arrangement 21, which comprises controlrelays 24, 24 and II and a brightness selector controller 3 I.

In this instance, the brightness selector controller 2| is of themanually operable type, and comprises a movable drum 32 having aplurality of segments 32, 24, I4 and 24 thereon, which are disposed toengage stationary contact fingers 21, ll, 22 and 44. The drum may beactuated by means of an operating handle 4| connected thereto by meansof a shaft 42, the operating handle being provided with an extension 42carrying a detent 44 disposed to engage any one of the three notches 4|in the stationary plate 46 which determines the operating position ofthe drum.

The controller II is utilized to predetermine or preselect which one ofthe brightness control relays 22, 2| and II is to be operated. when thecontroller is in the first position x, as shown, an

which are disposed to engage the stationary ilngers I, 62, 62, 44 and85, respectively. The drum is connected to the operating handle 56through a shaft 61, and the handle is provided with an extension I!provided with a locking detent 42.

In this instance, the selector relays 49 through 52 are provided withnormally closed contact members which short-circuit their associatedlighting circuits. Any one of the lighting circuits may be renderedeffective for energization by opening the relay, which performs the samefunction as that of connecting the lighting circuit to the source ofsupply. Any other suitable arrangement may be used to produce the samegeneral results.

when the controller i2 is in the position a, as shown, an operatingcircuit is partially established for the selector relay 48 through theconductor ll. Operation ot the controller to positions b, c and dlikewise partially establishes operating circuits for the selectorrelays II, II and 52, respectively.

In order to provide for automatically eifecting the disconnection of thelighting circuit in operation from the power source upon failure of thecircuit, such, for example, as a break in the con ductor comprising thesecondary circuit of the transformer il, a protective relay device 14 isutilized. This device may comprise a delayed opening relay 14 havingnormally closed contact members 15, and a second relay 16 also havingnormally closed contact members 11. The operation of this device will bedescribed more in detail in the description of the operation of thesystem.

In describing the operation of the system, it will be assumed that theoperator desires to utilize the lighting circuit II and operate it at alower brilliancy than normal. As described hereinbefore, the setting ofthe controllers 2i and I, as shown, is such as to preselect thislighting circuit and predetermine its brightness when energized.

The energization of the selected lighting circuit at the selectedbrightness is controlled by a master switch ll connected in the controlcircuit which is energized from the control source 44, the controlarrangement being such that the operation of the master switch 18effects the simultaneous operation of the main switch 20 and thepreselected control and selector relays-in this instance, the relays Illand 49.

The control is also arranged to provide for effecting the automaticrelease of the line switch 24 in the event that an attempt is made byuse of either one of the controllers II and II to change to a diluentbrightness or to a diilerent lighting circuit while the master switch 19is closed.

These features are provided by extending the control circuit for theline switch 29 and control and selector relays through suitableinterlocking switches on the controllers 3| and 33. In this instance,the controllers 3| and 53 are so arranged that, in the event theactuating handle is operated to release the drum for movement, theoperatiing circuit for the line switch, etc., is interrupted. Anysuitable switch arrangement may be utilized. However, in this instance,it is shown on the controller 3| in the form of a pair of contact ringsiii and 82 bridged by a contact element 93 carried on the extension 43of the controller handle. The construction of controller 53 isidentical, and need not be described in detail except to point out thatthe contact rings are indicated by numerals 94 and 95 and the bridgingcontact element by 99. It will be understood that this arrangementprovides an eil'ective electrical interlock, and while it does notprevent operation of either one of the controllers 3i and 53, it doesprevent any new selection of lighting circuits or brightness thereofwithout first deenergizing the circuit in use.

When the master switch 19 is closed, an oper-- ating circuit isestablished from the upper conductor of the source 89 through the masterswitch 19, conductor 91, the contact rings 8! and 82 bridged by theelement 93, conductor 98, contact rings 94 and 95 bridged by the element96, conductors 99, 9| and 92, contact members 15 of the protectivedevice, operating coil 93 of the line switch and conductor 94 to theother side of the source 89. The energization of this circuit efiectsthe operation of the line switch 29 to connect the regulatingtransformer I1 to the power supply.

Concurrently with the establishment of this circuit, the operatingcircuits for the control relay 39 and selector relay 49, which werepartially established by the setting of the controllers 3| and 53 inpositions a: and a, respectively, are also completed through thecontroller drums. The operating circuit for the selector relay 49extends from the energized conductor 89 through contact fingers Bi and62 bridged by the segments 55 and 56, conductor 1|, coil of the relay49, and the common conductor 94 to the other side of the control source99. The energization of this circuit eiIects the opening of relay 49 andrenders the lighting circuit i9 effective. The operating circuit for thecontrol relay 39 extends from the energized conductor 9i through thecontact fingers 31 and 38 bridged by the segments 33 and 34, conductor41, coil of the relay 39 and common conductor 94 to the other side ofthe control source 89.

Since all three of these circuits are established at the same time, itwill be understood that operation of the main switch and the control andselector relays takes place at substantially the same time.

As stated hereinbefore, the protective device 13 functions toautomatically open the line switch in the event that a break occurs'inthe secondary circuit of transformer i1. In order to effect this result,the relay element 19 of the protective device has its operating coil 95connected in series with the lighting circuit in operation across thetransformer 2|, so that, as soon as the lighting circuit is energized,the relay is operated to open its contact members 11. As shown, thesecontact members are connected in series with actuated to its openposition, which opens its I contact members 15 and deenergizes theoperating circuit of the line switch. In order to delay the opening ofthe contact elements 15 of the relay element 14 a sumcient length oftime to effect the closure of the line switch, the opening operation ofthe relay element 14 is delayed in any suitable manner, such, forexample, as by the use of a dashpot 91 as shown. By means of thisarrangement, the contact members 15 15 are held closed until the lineswitch 29 closes and eflects the opening of the contact members 11 ofthe relay element 19. After these contact members are opened, the relayelement 14 remains closed until such time as the lighting circuit inoperation becomes open circuited to effect closing of the relay element16 and subsequent energization of the relay element 14.

While in the system disclosed manual control is utilized, it is to beunderstood that autcmatic control of both the brightness controller andrunway selector controller may be readily provided. For example, thebrightness selector controller may be automatically operated orcontrolled by a device responsive to atmospheric 30 transmissivity,which may embody the controller as one of its elements, or by means ofany other remote control arrangement. Likewise the runway selectorcontroller may be operated or controlled by a wind vane device, whichmay embody the controller as one of its elements, or by means of anyother remote control arrangement.

Any desired number of brightness control positions may be provided, andany desired number of runway lighting circuits may be controlled.

Likewise the brightness and runway selector controllers and masterswitch may be interlocked mechanically, instead of electrically, asdisclosed.

It is also to be understood if but a single lighting circuit isprovided, the brightness control also may be used with equal advantage,as

the desirability of providing brightness control applies to aone-circuit installation as well as to an installation having aplurality of lighting circuits.

The system illustrated utilizes series light ing circuits, but it willbe apparent that the principles of the invention may be also applied to1ttls e control of multiple or parallel lighting circu In view of theforegoing description of the exemplary embodiment of my invention, itwill be apparent that there is provided a control system for lightingcircuits which is particularly adapted for the control of contactlighting circults of airports and the like, and which promakes itpossible for the operator to readily select the runway desired anddetermine its brightness, as well as the turning of the runway lightsoff and on from a remotely located control room, and the system is ofsuch nature that these operations may be effected by a minimum number ofoperations.

It may be stated in conclusion that, while the illustrated exampleconstitutes a practical embodiment of my invention, I do not wish tolimit myself strictly to the exact details herein illustrated, sincemodifications of the same may be made without departing from the spiritof the invention as defined in the appended claims.

I claim as my invention:

1. The combination with a plurality of lighting circuits and a powersource therefor, of trans former means disposed to be connected to thepower source for supplying currents of different predetermined values tothe circuits, a main switch for connecting the transformer means to thesource, means including a plurality of selector relays selectivelyoperable to determine which of said lighting circuits is to beenergized, means including a plurality of control relays selectivelyoperable to effect the connection of the selected circuit to thetransformer means and determine the current value to which it is to besubjected, and means for collectively controlling the operation of themain switch and control and selector relays.

2. In a control system for lighting circuits, comprising, a constantcurrent regulating transformer, a line switch operable to connect saidregulating transformer to a supply source, an autotransformer having aplurality of different output current taps connected to the outputterminals of the regulating transformer, means including a plurality ofcontrol relays for preselecting the output current tap on theautotransformer to which a selected lighting circuit is to be connected,means including a plurality of selector relays for preseiecting adesired lighting circuit for operation, and means for collectivelyeifecting the operation of the line, control and selector switches 'toconnect the selected lighting circuit to the selected output current tapand the regulating transformer to the supply source.

3. A control system for lighting circuits, com prising, a constantcurrent regulating transformer, a main switch operable to connect saidregulating transformer to a supply source, a transformer connected tothe output side of the regulating transformer and having a plurality ofdifferent current taps, a plurality of selector relays each of which isoperable to render an associated lighting circuit effective forenergization, means operable to preselect a desired selector relay foroperation, a plurality of control relays each operable to connect theselected lighting circuit to one of the current taps of the transformer,means operable to preselect the desired control relay for operation, anda master switch operable to effect the collective operation of the main,selector and control switches.

4. A control system for a plurality of lighting circuits, comprising, aconstant current regulator for supplying current to the lightingcircuits, a main switch for connecting the regulator to a power source,a transformer connected to the output side of the regulator and havingtaps for subjecting the lighting circuits to different values of currentwhen connected thereto, a plurality of control relays one of which isassociated with each tap for connecting a lighting circuit thereto, aplurality of selector relays each associated with a lighting circuit, amanuallyoperable switch for selecting any one of the control relays foroperation, a second manuallyoperable switch for selecting any one of theselector relays for operation, and a master switch for simultaneouslycontrolling the operation of the main line, control and selectorswitches.

5. The combination with a plurality of groups of lighting units havingthe units of each group connected in series circuit relation and thegroups connected in series to a supply circuit, of a group of selectorrelays. each relay of the group being operable to render its associatedgroup of units eiiective for energization from the supply circuit,control means for selectively predetermining which of said selectorrelays is to be operated. transformer means operable to energize any oneof the selected groups of units with substantially constant currents ofdifferent values, a plurality of control relays each operable to connectthe supply circuit to the transformer means for cu ergization with acurrent of one of the different values, additional control meansoperable to selectively predetermine which one of the control relays isto be operated, a main switch operable to connect the transformer meansto a power source, and a master switch operable to effect the collectiveoperation of the main switch and the selected selector and controlrelays whereby the selected group of units is energized at the selectedcurrent value.

6. A control system for lighting circuits, comprising, transformer meansoperable to maintain substantially constant currents of diiferentpredetermined values in a lighting circuit, a main switch for connectingthe transformer means to a power source, a plurality of selector relayseach operable to render its associated lighting circuit effective forenergization, a first controller operable to predetermine the desiredselector relay for operation, a plurality of control relays eachoperable to connect a selected lighting circuit to the transformer meansto be energized by a constant current of the desired value, a secondcontroller operable to predetermine the desired control relay foroperation, a master switch for controlling the operation of the mainswitch and the selector and control relays which have been predeterminedfor operation, said master switch and the first and second controllersbeing electrically interlocked to effect the opening of the main switchin response to the attempted operation of either one of the first andsecond controllers when the master switch is in its closed position andthe lighting circuit is energized.

7. A control system for lighting circuits, comprising, a regulatingtransformer operable to maintain a substantially constant current in alighting circuit, a main switch for connecting the regulatingtransformer to a power source, a transformer connected to the outputterminals of the regulating transformer and having a plu rality ofoutput terminals of different current values for operating a connectedlighting circuit on different predeterminedvalues of constant current, aplurality of control relays each operable to connect a lighting circuitto one of said output terminals, a manually-operable brightnesscontroller for preselecting the desired control relay for operation, aplurality of selector relays each operable to render an associatedlighting circuit effective for energization, a manually-operableselector controller for preselecting the desired selector relay foroperation, each of said controllers being provided with actuating meansincluding a normally closed switch. an energizing circuit for the mainswitch and control and selector relays extending through the normallyclosed switches on the controllers, and a master switch for controllingsaid energizing circuit.

8. A control system for lighting circuits, corn. prising, a regulatingtransformer operable to maintain a substantially constant current in alighting circuit, a main switch for connecting the regulatingtransformer to a power source, an autocurrent transformer connected tothe output terminals of the regulating transformer and having aplurality of output terminals of different current values for operatinga connected lighting circuit on different predetermined values ofconstant current, a plurality of control relays each operable to connecta lighting circuit to one of said output terminals, a manually-operablecontroller for preselecting the desired control relay for operation, aplu rality of selector relays each operable to render an associatedlighting circuit effective for energization, a manually-operablecontroller for pre-,

selecting the desired selector relay for operation, each of saidcontrollers being provided with actuating means including a normallyclosed switch, an energizing circuit for the'main switch and control andselector relays, a protective relay device including a delayed openingrelay and a second relay for controlling the energization thereof, saidenergizing circuit extending through the normally closed switches on thecontrollers and the contact elements of the delayed opening relay of theprotective device, and a master switch for controlling the energizingcircuit, said second relayof the protective device being operable inresponse to an open circuit condition of the connected lightingcircuitfor energizing the delayed opening relay to interrupt theenergizing circuit to effect the opening of the main switch.

9. A brightness selector control system for a lighting circuitcomprising, transformer means having a plurality of output taps operableto energize the circuit at different predetermined degrees ofbrightness, control means including a main switch operable to connectthe transformer means to a power source, and additional control meansincluding a plurality of control relays selectively operable topreselect the output tap of the transformer means to which the lightingcircuit is to be connected and thereby preselect the degree ofbrightness of the circuit when connected to the output taps of thetransformer means, and means including one of said control relaysresponsive to the operation of the ent predetermined current outputs ofa constant current source of supp y. and means for collectivelyeifecting the operation of theselector and control relays to effect theconnection of the selected lighting circuit to the selected outputterminals of the source.

11. A control system for a plurality of series lighting circuitscomprising, a transformer means operable to maintain substantiallyconstant currents of different predetermined values in a lightingcircuit, a. main switch for connecting the transformer means to a powersource, means including a plurality of selector relays forpredetermining which one of the lighting circuits is to be connected tothe transformer means, means including a plurality of control relays forpredeterrnining the connection of the selected one of the lightingcircuits to the transformer means at the desired predetermined currentvalue, means for collectively controlling the operation of the main lineswitch. selector and control relays to effect the energization of theselected lighting circuit at the selected predetermined current value,and means operable in response to an open circuit condition of theconnected lighting circuit to eflect the opening of the main line switchto disconnect the transpower source, an autocurrent transformerconnected to the secondary winding of the regulator and having outputterminals providing different predetermined constant currents, andcontrol means including a plurality of control and selector relaysselectively operable to preselect any one of the series lightingcircuits for subsequent connection to any one of the different outputterminals of the autocurrent transformer, and a master switch' operableto simultaneously effect the closure of the main switch and operation ofthe control and selector relays, thereby to eflfect the energization ofthe selected series lighting crirlcuit with a constant current of theselected 13. A system for selectively controlling the degree ofbrightness of a lighting circuit comprising, transformer means providedwith a plurality of output taps each of which produces a predetermineddegree of brightness of the lightins circuit when said circuit isconnected thereto, switch means operable to connect the transformermeans to a power source, selector means including a plurality of controlrelays each individual to an output tap operable to preselect a desiredoneof said plurality of output taps on the transformer means forconnection to the lighting circuit, and control means cooperative withsaid selector means operable to eflect the operation of said switchmeans and one of said control relays individual to the selected outputtap to eil'ect energization of the lighting circuit at the degree ofbrightness determined by the output tap to which it is connected.

HARRY E. LIPPMAN.

